Piston



Aug. 30, 1932. J, plAMOND 1,874,925

PISTON original Filed July 51. 1926 s Sheets-Sheet 1 TOR Aug. 30; 1932. J. E. DIAMOND PISTON 5 Sheets-Shee 3 Original Filed July 31, 1926 ATTORNEY Aug. 30, 1932. J. E DIAMOND 5 Sheets-Sheet 4 0 'g' 1 Filed July 31. 1926 C I I z INVENIOR ATTO NEY -INVENTOR y ATTORNEYv J. E. DIAMOND Original Filed J 1y 31' 1926 5 Sheets-Sheet 5 Aug. 30, 1932.

Patented Aug. so. 1932 UNITED STATES PATENT OFFICE JAMES E. DIAMOND, or New Yonz, N. Y., ASSIGNOR r BonN ALUMINUM & BRASS f g conrom'rIoN, or DETROIT, MICHIGAN, A CORPORATION or MICHIGAN PISTON Application filed July 81, 1926, Serial No. 126,110. Renewed November 1, 1930.

I This invention relates to apiston, particularly to a piston made of light weight alloy and'designed for use in internal combustion engines.

i A particular object of the invention is the provision of a piston of the type referred to in which efiective means is provided for controlling the expansion of the upper part of the skirt. Variousexpedients have been resorted to inorder to control this part of the skirt, such as the provision of a steel ring embedded. in the wall of; theskirt, none of which are practicable commercially. J Applicant overcomes the defects in the prior art and produces a piston that can be conveniently and economically manufactured.

-' vWhile preferred embodiments of the invention are disclosed for purposes of illustration, it should be understood that various 'changes may be made in the structure without departing from the spirit of'the invention as hereinafter set forth and claimed.

" In the drawings;

Fig. 1 is a section through an engine 2 equipped with a piston constructed according to the present invention; g

Fig. 2 is an elevation of the piston shown in Fig. 1);

Fig. 3 is a section on line 33 of Fig. 2;

Fig. 4 is an enlarged detail view showing a modified structure;

Fig. 5 is an elevation of a modified piston; V Fig. 6 is a section on line 6-6 of Fig. 5;. Fig. 7 is a'section on line 7' 7 of Fig. 6; 1

i Fig. 8 is an elevat ion of a further modification; Fig. 9 is a section on line 9-9 of Fig. 8;

Fig. 10 is a section on line 10-10.of Fig. 9; I Fig. 11 is a section through a mold showing the method of molding a further modification; Fig. 12 is a sectionthrough a piston resultin from the molding process of Fig. 11;

ig. 13 is a section on line 13-13 of 4 Fig. 12

Fig. 14 is'a section through a mold showifng the method of molding another modified Fig. 15 is an elevation of the piston-resulting from the molding process of Fig. 14;

Fig. 16 is a section on line 16-16 of Fig. 15. At the outset it should be noted that the diameter of the piston across the upper end of the skirt is the one most important to control, since this part of the skirt is normally the hottest and because this part of the piston must be maintained in proper clearance relation? to the cylinder wall to prevent slapping. This part of the skirt is also the hardest to control because of its attachment to the freely-expanding head and because of v the difficulties arising if thevcontrol means causesdistorti'on of the-skirt. The present invention solves the problem by using a ring member to control the skirt without producing distortion and provides a structure that can be produced commercially.

Referring to the drawings more particularly, the piston 10 is illustrated as being of the type shown in Patent No. 1,153,902 granted to G. E. Franquist, Sept. 21, 1915.- A groove 11 is formed in the outer circumference of the piston above the pin bosses and circling the upper ends of the skirt segments, while an aperture 12 opens from the groove 11 and extends through the skirt. A' strip 13 of relatively inexpansible material suchas steel clock spring is wound around the groove 11 and its overlapping ends are spotwelded together at 14, the aperture 12 providing ac cess for the welding implements.

It will be evident that when this piston is heated the steel band will restrainthe outward expansion of the skirt and will cause the skirt segments" to expend circumferentially, tending to close upthe slots .15 in the manner indicated in Fig. 4. While the invention has been illustrated as applied to a Franquist piston it should be clear that the device can be used on any piston having pro-.

-V1S10I1 for absorblng the circumferentlal expansion of the skirt material.

In the piston illustrated in Figs. 5, 6 and 7, instead of a single band encircling thepis ton two semicircular bands 16 and 17, each extending slightly more than half way around the piston, are mounted in side-byside relation. Each band is mounted in a groove similar to the groove 11 of Fig. 1 p and the ends of the bands are anchored by countersunk screws 18, 19, 20 and 21, spotof said opposite boss-carrying portions and welded in place. As this piston becomes heatencircling the upper ends of said bearing ed the circumferential expansion of the skirt wall portion.

material carries the screws 19 and 20 apart In testimony whereof I aflix my signature.

and does the same thing with screws 18 and 21, on account of the fact that the skirt material expands faster than the material of the bands. This action results in contracting bands 16 and 17 in relation to each other, thereby reducing the resultant diametrical exansion below what it would be if a single and as in Fig. 1 were used. By varying the amount of overlap between the semi-circular bands different degrees of control over the skirt expansion can be secured.

The piston of Figs. 8, 9 and 10 is controlled in the manner just described, but instead of two semi-circular bands a single band 22 is wound spirally around the piston with its ends overlapped and fastened to opposite sides of one of the boss-carrying skirt segments 23 bv spotwelded .screws.

Fig. 11 shows a method of casting a piston in a permanent mold. A continuous control ring 24 of suitable material is heldin place between the two parts 25 and 26 of the mold body; the removable core pieces 27, 28 and 29 are then moved into position and the piston is poured. This is'a simple and expeditious method of producing the piston shown in Fig. 12, which has an integral control ring cast in place about the skirt in a position corresponding to that of ring 13 in Fig. 2.

In the method of Fig. 14 the integral ring 30 is held in position about the removable core and this piston is cast about the'ring,

which becomes thereby substantially part of.

the piston. In this piston the ring is located on the inside of the skirt and acts as a brace to prevent collapse of the skirt under stress.

I claim A piston for an internal combustion engine comprising, a head section, wrist pin boss-carrying portions depending from said head section. a pair of diametrically opposite bearing wall portions separated along their upper ends from said head section, each bearing wall portion lying between said bosscarrying portions and being integral with and yieldingly connected to said boss-carrys ing portions along each side edge, and control means of lower coefficient of expansion than the piston body completely encircling the piston body betweenthe bosses and the upper ends of the bearing wall portions and serving to restrain the outward expansion of said yieldingly supported bearing wall portions in accordance with the thermal expansion .and contraction of said control means, rather than, the thermal expansion of the piston body, said bearing wall portions being movable radially inwardly in response to excessive cylinder wall pressure, said control means comprising a pair of semi-circular members each secured to the upper portion JAMES E. DIAMOND. 

